Current bistability in a weakly coupled multi-quantum well structure: a magnetic field induced ‘memory effect’

Abstract

A study of magnetotunnelling in weakly coupled multi-quantum wells reveals a new phenomenon which constitutes a kind of memory effect in the sense that the electrical resistance of the sample after application of the magnetic field is different from before and contains the information that a magnetic field was applied previously. The change in the electric field domain configuration triggered by the magnetic field was compared for two samples, one strictly periodic and another with a thicker quantum well inserted into the periodic structure. For applied biases at which two electric field domains are present in the sample, as the magnetic field is increased a succession of discontinuous reductions in the electrical resistance is observed due to the magnetic field-induced rearrangement of the electric field domains, i.e. the domain boundary jumps from well to well as the magnetic field is changed. The memory effect is revealed for the aperiodic structure as the electric field domain configuration triggered by the magnetic field remains stable after the field is reduced back to zero. This effect is related to the multi-stability in the current–voltage characteristics observed in some weakly coupled multi-quantum well structures.

Optimization of Nanostructured Devices Using Self-consistent Calculations

“…A self-consistent analysis of the effect of a larger well introduced in the middle of a superlattice was presented in (7). In this case, even for a qualitative understanding of electrical dynamics in such a structure, the self-consistent computations were needed (8).…”